Align View to Current Transform Orientation
Test script to put all 3d view areas in context screen into same orientation as first custom scene orientation
import bpy
from mathutils import Matrix
context = bpy.context
# put all view_3d areas in screen into screen.orientation[0]
scene = context.scene
screen = context.screen
for o in scene.transform_orientation_slots:
    if o.custom_orientation:
        orientation = o.custom_orientation

print(&quot;Using &quot;, orientation.name)
view_rot = orientation.matrix.to_quaternion()

view3dareas = [a for a in screen.areas if a.type == 'VIEW_3D']
for a in view3dareas:
    r3d = a.spaces.active.region_3d
    r3d.view_rotation = view_rot

To make it change from camera perspective would need something like
    if r3d.view_perspective == 'CAMERA':
        r3d.view_perspective = 'PERSP'

To look &quot;from above&quot; from this orientation
rot = Matrix.Rotation(radians(-90), 3, 'X')
#view_rot = (rot * orientation.matrix).to_quaternion()
view_rot.rotate(rot)